1. Field of the Invention
The present invention relates to new 1,3,4-thiadiazole derivatives useful as antiulcer agents of the general formula (I): ##STR3## wherein R.sub.1 represents a group of the formula: ##STR4## and R.sub.2 represents an amino, lower alkylamino, cyclohexylamino, benzoylamino, mercapto or lower alkylthio group and a process for producing the same.
The compounds of the formula (I) are new compounds having an excellent antagonism to histamine H.sub.2 receptors and useful as long lasting inhibitors against secretion of acid in the stomach or antiulcer agents.
2. Description of the Prior Art
There have been known numerous compounds antagonistic to histamine H.sub.2 receptors such as cimetidine (U.S. Pat. No. 3,950,333) and ranitidine (U.S. Pat. No. 4,128,658). However, they are not always satisfactory, since they have some adverse reactions and their effect of inhibiting the secretion of acid in the stomach is only transient to require an increase of the dose and number of times of the administration.
After synthesis of numerous compounds and intensive investigations made for the purpose of solving these problems, the inventors have succeeded in producing new compounds (I) having quite excellent effect of inhibiting the secretion of acid in the stomach, pepsin-inhibitory effect and antiulcer effect.